Abstract: In order to improve the blood flow characteristics near the wall after vascular stent implantation, inhibit the adhesion of platelets, lipids and other substances in the vascular stent and reduce the probability of restenosis in the stent, regular hexagonal convex micro textures with different heights were designed on the inner surface of the tubular vascular stent based on the principle of bionics.The effects of different height micro textures on the blood flow near the wall during systole and diastole were studied by finite element method. The results show that compared with non textured stents, stents with micro texture on the inner wall can effectively improve the blood flow state. When the blood flow velocity reaches the peak value during cardiac systole, the blood flow velocity under stents with micro texture height of 35 μm can be increased by 0.78%, and that under stents with micro texture height of 50 μm can be increased by 8.93%; When the diastolic blood flows smoothly, the blood flow velocity under the stent with 35 μm micro texture height can be increased by 2.20%, and the blood flow velocity under the stent with 50 μm micro texture height can be increased by 14.37%. Especially when the blood velocity reaches the peak, the blood near the wall appears disturbance and stagnation zone. With the increase of micro texture height, the amplitude of blood disturbance increases gradually; When the blood flow is in a stable state, the blood produces vortex and backflow near the wall. The higher the micro texture, the smaller the blood backflow and the greater the vortex intensity. Compared with non textured stents, micro textured stents can effectively improve the blood flow characteristics near the wall, improve the blood flow velocity and disturbance near the wall, and reduce the risk of restenosis.

Key words: micro texture, vascular stent, near wall, blood flow velocity, finite element analysis, Ansys, hydrodynamics